The couple had a headline-making beginning, with implications of infidelity and timeline analysis coming from the tabloids the moment Pitt announced his separation from then wife Jennifer Aniston. Whether Brad and Angelina had a physical affair or emotional affair before becoming an official couple — after Pitt famously left his wife — is still up for debate, and something we will likely never know.

It was in 2006, Jolie said of working on the film with Pitt that she realized, “‘God, I can’t wait to get to work.’ … Anything we had to do with each other, we just found a lot of joy in it together and a lot of real teamwork. We just became kind of a pair.”

And, as a refresher, Jolie met her second husband, Billy Bob Thornton, on the set of their 1999 film Pushing Tin. At the time Thornton was engaged to actress Laura Dern, who then missed her chance be his fifth wife. Dern said of the situation, “I left our home to work on a movie, and while I was away, my boyfriend got married, and I’ve never heard from him again.”

While the numbers vary by study, the probability of someone cheating during the course of a relationship varies between 40 and 76 percent, according to Science Daily. However, when we spoke with licensed psychotherapist Stacy Kaiser, she pointed out that “the cheating statistics are [made up of] people who will admit it, and people who’ve been caught. The numbers are likely much higher.”

But what happens when the two people having an affair — emotional or physical — end up together? The outlook isn’t great. Kaiser points out that second marriages (and third, in Jolie’s case) have a higher rate of divorce, as do marriages that come out of affairs. “You put that combination together,” says Kaiser, “and you’re walking into a challenging situation.”

Often, an affair offers excitement, emotional escape, sexual intensity, and maybe even a newfound raison d’être. “I’ve had a lot of clients tell me that their new open, public relationship is boring,” explains Kaiser. “There was excitement in the hiding, and that boredom can make a person seek excitement elsewhere.”

The other issue? Insecurity. “Oftentimes with people who end up together, one or both of the people are more insecure about cheating,” said Kaiser. “They did it before — that insecurity and lack of trust needs to be talked about up front, because secret concerns and stress create bigger problems. If you’re worried about it, you need to talk about it.”

A lot of this comes down to character, said Kaiser. “There are people who cheat and will never do it again, and there are people who don’t actually have a moral problem with cheating and will do it again.”

Kaiser offers a word to the wise: “If someone has been capable of being disrespectful and dishonest with someone they cared about in the past, there is a possibility they can do that to you. Anyone can cheat, but this is a bigger risk.”